Process of making collapsible and expansible vessels.



PATENTED MAR. 5

W. M. FULTON. v PROCESS OF MAKING OOLLAYPSIBLE AND EXPANSIBLE VESSELS.

APPLICATION FILED 1107.2, 1904:.

l 7 I uwnifo c q Vihwoow I... m 6 am WEsToN M. FULTON, OF KNOXVILLETENNEsSEE, AssIeNo TO THE FULTON COMPANY, or or MAINE.

KNOXVILLE, TENNESSEE, A CORPORATION PROCESS OF MAKING COLLAPS IBLE AND EXPA NSIBLE.VESS ELS- Specification of Letters Patent.

' .Patented March 5, 1907.

Qfiginal application filed Jilly 19, 1904, Serial No. 2 17,2 86. Divided and this application filed November 2, 1904. Serial No. 23 1.120.

To all whoni, it may concern: Be it known that I, WESTON M. .FULToN,

I of Knoxville, Tennessee, have invented a per and brass, and which resist- 'act1on of air and moisture.

- of such coatings are porous and crack in use,

new and useful Process of Making Collapsible and Expansib'le Vessels, which invention is fully set forth in the following specification. This invention relates to a process of treat ing sheet metal, and has for its object the production of walls for corrugated vessels which shall have substantially uniform density and great flexibility and durability. in a previous application for Letters Patent, Serial No. 213,864, filed June 23, 1904, I-

have described a ,process for electrically welding sheet steel. Collapsible vessels of sheetsteel having seams electrically welded have great durability and flexibility; but, it is desirable t times to have the flexible wall of a collapsl le and expansible, vessel made of metals not readily wcldable, such as copthe oxidizing Such vessels are especially useful when the vessel is to be employed, for example, as the expansible por' tion of a steam-gage or as the thermosensitive portion of devices for gaging-the temperatures of liquids. In-devices of thischaracter steel readily oorrodes and is not serv- I lceable even when' protected by metal coat-' ings of tin, zinc, or nickel, because the best exposingthe iron to. oxidation and rusting.

In my application, Serial N 0. 217,286, filed July 19, 190 1, I have described corrugated sheet-metal walls for use in collapsible and expansible vessels and the process of making the same and have claimed the article therein. In the present application, which is a division of application Serial No. 217,286, I

have described and c'laimedthe process of making such articlesof manufacture. It is desirable to use in flexible vessels of this kind a metal or alloy that will not readily corrode, such as co per or brass. In making the walls of collapslble vessels out of copper or brass it has been found'that the seams readily give way to bending strainsand break.

'lhere fore seamless drawn tubing is preferable for constructing'such vessels;'but even seamless drawn tubing soon develops weakness at the bends in the corrugations, which unfits it for use in constructing the walls of corrugated colla sible vessels. Injthe manufacturev of sea ess tubing one of the common methods in use is to draw the tube between a mandrel and die. This operation results in condensing'and hardening the oustide layers of the metal wall, leaving the inner portion of the tion under influence of heat, and also in elasticity. In the case of brass tubingmade in this way the coefficient of expansion of the dense layers differs so widely from that'of the inner layer that the ordinary changes in'atmospheric temperatures causes the tube to crack. Although annealing reduces this difference in molecular structure between the layers and prevents cracking for ordinary purposes, yet

such annealing fails to render the drawn.v

tubing servicable for making the Walls of flexible corrugated colla sible vessels which are to withstand repeate expansion and compression.

To better understand this invention and how the difficulties above noted have been overcome, reference is had to the accompanying illustrations, in which Figure 1 shows a tube drawn from a cast ingot in the usual way. Fig. 2 is a longitudinal section of the same. Fig. 3 is the tube of Fig. 1 corrugated, and Fig. 4 shows the tube on a mandrel.

1 indicates a diedrawn seamless tube of metal, such as brass, having its end 2 highly magnified for the sake of illustrating the molecular condition of the wall.

3 and 4 are the inner and outer portions of the tube, which have been compressed and hardened by contact of the mandrel and die,"

respectively, in the course of its manufacture,

and 5 is the' intermediate layer farthest drawing. The relative density of the severa layers is also indicated by the dotted shad ing. It will thus be seen that the wall of a diedrawn tube is not of, homogeneous structure in passing through the wall from one side to the other, but is composed of layers more or less clearly defined which possess diflerent degrees of hardness and different coefficients of expansion. By reason of this lack of uniform constitution deleterious effects result into a corrugated collapsible vessel.

and become serious when such tubing is made In Fig. 3 is illustrated the walls of a corrugated vessel shown in section. 6 designates a single corrugation. If the wall is collapsed, the outer layer 4 will-be compressed, while the layer 3.will be drawn out. The middle layer 5, which is relatively neutral, will serve to intensify the strain on layers 3 and 4 by virtue'of the fact that it separates them from ingot.

the objections noted and which shall be of more uniform density throughout the thickness of the wall and be "flexible and durable.

To accomplish these objects, one or more of the non-homogeneous layers composing the sheet of metal is removed, preferably by the mechanical action of a tool; but the removal of the layer or layers may be effected by means of a suitable. solvent or by electrolysis.

' To illustrate one method of carrying out.

the invention, a seamless tube is formed, preferably of brass, by any of the well-known methods, such as by drawing atube from a cast This tube is then chucked in a lathe, and by means of a boring bar and tool the inner condensed layer is removed. The tube is then placed on a mandrel 7, (shown in Fig.

4,) having its surface trued and of just suflicient diameter to fit closely the inslde of the tube 1. This mandrel, with its tube upon it, is then chucked in a lathe and the outer surface removed. The remainin tube is then corrugated deeply, as indicate in Fig.3, and there results a flexible elastic corrugated wall which may be elongated and compressed and which will withstand repeated strains without danger of cracking. r

In. illustrating this invention a seamless die-drawn metal tube has been taken and the two condensed surfaces removed; but the method is equally applicable to sheet metal not in the form of a tube, such as sheet metal which has been rolled and has its outer layers thereby hardened and before or after shaping it into its final configuration. The tube may not be die-drawn, but may be made from sheet metal, preferably sheet-brass, by bending the sheet into cylindrical form, butting the edges, and brazing. The tube is then treated in a similar manner as one die-drawn and then corrugated'to form the flexible elas- 6c tic wall.

Although excellent results are obtained by removing both surfaces of the sheet metal, yet only one may be removed and the advantages of the process be apparent in the result. It is found,however, that by removing fifty per cent. to eighty per centjof the thickness of "the wall the best results are obtained, and 1 preferably use seamless drawn tubing; but seamless brazed tubing may be used. The removal of the layers is performed in the same manner as with drawn tubing. This method greatly improves the walls of collapsible vessels made of metals not iisu ally weldable, imparting to the wall great durability and flexibility. Brass and copper sheet metal thus treated and corrugated are greatly improved and better adapted for use in constructing the walls of corrugated expansible and collapsible vessels.

What is claimed is 1. A process of making substantially homogeneous flexible corrugated-metal walls for expansible and collapsible vessels from rolled or drawn sheet metal having its outer surfaces more condensed than the interior portion, consisting in removing said condensed surfaces and corrugating the substantially homogeneous remaining portion of said sheet.

2. A process of making substantially homogeneous flexible corru gated-metal walls for expansible and collapsible vessels from metal tubing having surfaces more condensed than the interlor portions of the wall 9 5 of the tubing, said process consisting in removing from said tubing the condensed surfaces of the walland corn-gating the sub stan tially homogeneous remaining portion of the wall of the'tubing.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

wEsToN M. FULTON. Witnesses:

JOHN S. BROWN,

W. -W. BERRY. 

